The present invention relates generally to emergency light sources, and, in particular, to emergency light sources suitable for illuminating areas such as hallways, stairways, elevator banks, and the like. In particular, the present invention is directed to a battery-operated emergency light source suitable for extended use during a power outage.
An area such as a hallway or a stairway may be illuminated during a power outage by a conventional emergency lighting system which generally consists of a light that is powered by a rechargeable battery. The rechargeable battery is usually connected to an electrical source via an electrical circuit and is charged conventionally continuously. When the power source fails, the system uses the stored energy to power the light. These emergency lighting systems, however, are meant to be brilliantly lit for a very limited period of time, for instance, during a brief power outage, and therefore do not last more than several hours, on the average. Once the power is restored, the rechargeable batteries can be charged again in preparation for the next power outage. In the event of an extended power outage, however, the rechargeable batteries become spent after a few hours, leaving the lights without power and unusable until the power returns. Once these rechargeable batteries are spent, light is no longer available, and the areas lit only by these lights become completely dark, creating dangerous conditions.
Most light bulbs, such as incandescent light bulbs used in conventional emergency light sources, are lit by heating filaments. These filaments burn out and dissipate heat and therefore waste energy. Once the filament burns out, the light bulb cannot be used, resulting in a short life of the bulb.
Additionally, rechargeable batteries typically used to power emergency lights do not have a long shelf life. They are self discharging and will become useless after about six months if it is not recharged during that time. Therefore, the rechargeable batteries require strict maintenance and must be charged on a regular basis. An alternative for rechargeable batteries is a building generator, which is big, expensive and requires an emergency fuel source which itself raises safety and storage problems. In fact, because of the expense of conventional emergency power systems, including the cost of providing an electrical source in the vicinity of the system, many existing buildings have no such systems, especially private houses and buildings built before codes required emergency lighting.
Accordingly, there is a need for an emergency light source that can be easily mounted on a fixture, ceiling, wall, and the like, can be battery operated and provide continuous light for more than 24 hours.